Macrolide and Ketolide Antibiotic Separation by Reversed Phase High Performance Liquid Chromatography

Twenty different macrolide and ketolide antibiotics were analyzed by reversed phase high performance liquid chromatography on an ODS-2 cartridge column. Each of these compounds was uniquely separated and purified by varying the flow rate. Retention times of the individual drugs were proportional to the flow rate of the mobile phase. Recovery of antimicrobial activity for most of the drugs was greater than 90% based on a microbiological assay of material recovered from the column. Retention times were related to structural differences between these antimicrobial agents

Unexpected Syntheses of seco-Cyclopropyltetrahydroquinolines From a Radical 5-Exo-Trig Cyclization Reaction: Analogs of CC-1065 and the Duocarmycins

Abstract: Analogs of the seco-cyclopyrroloindoline (seco-CPI), the DNA alkylation pharmacophore of CC-1065 and the duocarmycins, can be prepared through a 5-exo-trig radical cyclization of a free radical and a 3-chloro-2-allylic moiety. This manuscript reports an unexpected discovery that, depending on the structure and stability of the free radical, the cyclization process leads to the production of an appreciable amount of secocyclopropyltetrahydroquinolines 7a-d along with the seco-cyclopropoyltetrahydroindoline products (6a-e). For instance, free radical reaction of the bromoallylic chloride 5a produced an equal amount of 6-benzyloxy-N-t-butoxycarbonyl-3-(chloromethyl)furano[e]indoline (6a), and 7-benzyloxy-N-t-butoxycarbonyl-3-chloro-1,2,3,4-tetrahydrofurano[f]quinoline (7a). Three other examples that produced mixtures of indoline and quinoline products are provided. In only one of the examples reported in this manuscript, the 6-benzyloxy-N-t-butoxycarbonyl-3-(chloromethyl)benzo[e]indoline, was a seco-CBI precursor 6e formed exclusively, consistent with literature precedents

Unexpected Syntheses of \u3cem\u3eseco\u3c/em\u3e-Cyclopropyltetrahydroquinolines From a Radical 5-\u3cem\u3eExo-Trig\u3c/em\u3e Cyclization Reaction: Analogs of CC-1065 and the Duocarmycins

Analogs of the seco-cyclopyrroloindoline (seco-CPI), the DNA alkylation pharmacophore of CC-1065 and the duocarmycins, can be prepared through a 5-exo-trig radical cyclization of a free radical and a 3-chloro-2-allylic moiety. This manuscript reports an unexpected discovery that, depending on the structure and stability of the free radical, the cyclization process leads to the production of an appreciable amount of seco- cyclopropyltetrahydroquinolines 7a-d along with the seco-cyclopropoyltetra- hydroindoline products (6a-e). For instance, free radical reaction of the bromoallylic chloride 5a produced an equal amount of 6-benzyloxy-N-t-butoxycarbonyl-3- (chloromethyl)furanoe]indoline (6a), and 7-benzyloxy-N-t-butoxycarbonyl-3-chloro- 1,2,3,4-tetrahydrofuranof]quinoline (7a). Three other examples that produced mixtures of indoline and quinoline products are provided. In only one of the examples reported in this manuscript, the 6-benzyloxy-N-t-butoxycarbonyl-3-(chloromethyl)benzoe]indoline, was a seco-CBI precursor 6e formed exclusively, consistent with literature precedents

Sequence specific recognition of DNA by tailor-made hairpin conjugates of achiral \u3cem\u3eseco\u3c/em\u3e-cyclopropaneindoline-2-benzofurancarboxamide and pyrrole-imidazole polyamides

Hairpin conjugates of achiral seco-cyclopropaneindoline-2-benzofurancarboxamide (achiral seco-CI-Bf) and three diamides (ImPy 1, PyIm 2, and PyPy 3, where Py is pyrrole, and Im is imidazole), linked by a gamma-aminobutyrate group, were synthesized. The sequence-specific covalent alkylation of the achiral CI moiety with adenine-N3 in the minor groove was ascertained by thermally induced DNA cleavage experiments. The results provide evidence that hairpin conjugates of achiral seco-CI-Bf-gamma-polyamides could be tailored to target specific DNA sequences according to a set of general rules: the achiral CI moiety selectively reacts with adenine-N3, a stacked pair of imidazole/benzofuran prefers a G/C base pair, and a pyrrole/benzofuran prefers an A/T or T/A base pair. Models for the binding of hairpin conjugates 1-3 with sequences 5\u27-TCA(888)G-3\u27, 5\u27-CAA(857)C-3\u27, and 5\u27-TTA(843)C-3\u27 are proposed

Novel furano analogues of duocarmycin C1 and C2: design, synthesis, and biological evaluation of\u3cem\u3eseco\u3c/em\u3e-iso-Cyclopropylfurano[2,3-\u3cem\u3ee\u3c/em\u3e]indoline (\u3cem\u3eseco\u3c/em\u3e-iso-CFI) and \u3cem\u3eseco\u3c/em\u3e-Cyclopropyltetrahydrofurano[2,3-\u3cem\u3ef\u3c/em\u3e]quinoline (\u3cem\u3eseco\u3c/em\u3e-CFQ) analogues

The design, synthesis and biological evaluation of novel seco-iso-cyclopropylfurano2,3-e]indoline (seco-iso-CFI) and the seco-cyclopropyltetrahydrofurano2,3-f]quinoline (seco-CFQ) analogues of the duocarmycins are described. These novel analogues (4-7) were designed on the premise that the lone pair of electrons on the furano-oxygen atom could enter into conjugation with the isocyclopropylfuranoe]indolone (iso-CFI) alkylating moiety, formed from the loss of HCl in compounds 4-7. The seco-iso-CFI DNA alkylating pharmacophore was synthesized through a well precedented approach of 5-exo-trig aryl radical cyclization with a vinyl chloride. In our studies, in addition to the formation of the seco-iso-CFI product, an equal amount of an unexpected seco-CFQ product was also generated during the radical cyclization reaction. Like CC-1065 and adozelesin, using Taq DNA polymerase stop and thermal cleavage assays, the seco-iso-CFI compounds (4 and 6) and the seco-CFQ compounds (5 and 7) were shown to preferentially alkylate the adenine-N3 position within the minor groove of long stretches of A residues. A MM2 energy optimized molecular model of a 1:1 complex of compound 6 with DNA reveals that the iso-CFI compound fits snugly within the minor groove. Using a MTT based experiment, the cytotoxicity of compounds 4-7 were determined against the growth of murine leukemia (L1210), mastocytoma (P815) and melanoma (B16) cell lines. The concentrations of compounds required to inhibit the growth of these tumor cells by 50% is in the range of 10-ˆ’8M. These compounds were also tested against a panel of human cancer cells by the National Cancer Institute, demonstrating that the compounds exhibited a high level of activity against selected solid tumors. At a concentration of 0.0084μM (based on the IC50 of compound 17 (seco-CBI-TMI) against the growth L1210 cells), while compounds 4 and 17 were toxic against murine bone marrow cells as judged by a colony forming study of freshly isolated murine progenitor hematopoeitic cells, compound 5, a seco-CFQ compound, was significantly less toxic. Flow cytometric analysis of P815 cells that had been incubated for 24h with compounds 4 and 5 at their cytotoxic IC50 concentrations indicated the induction of apoptosis in a large percentage of cells, thereby suggesting that this might be the mechanism by which the iso-CFI compounds kill cells